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Biomedical subjects

P H Robinson

Publications and source records attributed to P H Robinson.

17 recordsLinked to original sources
PubMed1992

The phenylpropionic acid load test: experience with 72 children at-risk for beta-oxidation disorders.

The urinary excretion of metabolites of orally administered phenylpropionic acid (PPA) in 72 children, aged 2 days to 16 years, thought to be at-risk of medium acyl CoA dehydrogenase deficiency has been studied. Forty had presented as Reye Syndrome, 9 as a Reye-like syndrome and 24 were sibs of decreased RS, sibs of RLS cases or sibs of infants who had died suddenly and without explanation where an autopsy revealed the presence of very heavy fatty infiltration of the liver. These studies demonstrated that PPA metabolites are maximally excreted during the 3 hours following the oral load and that this urine collection should be diagnostic. PPA loading is a relatively simple, safe test which is part of the investigation of a patient suspected of having an inborn error of metabolism.

Acyl-CoA Dehydrogenase↗
PubMed1992

Effect of canola fat on ruminal and total tract digestion, plasma hormones, and metabolites in lactating dairy cows.

The effects of canola fat on digestion and metabolism were investigated by incorporating 0, 4.5, 9, 13.2, or 17.4% Jet-Sploded canola seed into a diet containing a 60:40 (DM) concentrate:forage ratio. The diets contained 16.5% CP, 30% alfalfa silage, and 10% whole-crop oat silage on a DM basis and were fed for ad libitum consumption as TMR to 10 ruminally cannulated Holstein cows in early lactation. Jet-Sploded canola seed supplementation did not change ruminal pH or NH3 N concentrations, but VFA concentrations declined with increasing level of inclusion. Apparent digestibilities of DM, OM, CP, NDF, and ADF were unaffected by level of inclusion of Jet-Sploded canola seed, but ether extract digestibility declined linearly, which resulted in similar ether extract absorption across the three diets supplemented with canola fat. Based on in sacco data, the percentages of ruminal digestion of OM and CP declined with increasing inclusion of Jet-Sploded canola seed. Plasma glucose and FFA concentrations tended to respond in a quadratic fashion, plasma insulin concentration declined linearly, and plasma glucagon and somatotropin concentrations were unaffected by dietary treatment. The results indicate that a positive productive response may be expected from dietary inclusion of about 5% Jet-Sploded canola seed, but the benefits of increased energy density associated with higher inclusion levels may be offset by reduced availability of energy in the rumen and decreased fat digestibility postruminally. The substantial effects of time postfeeding on ruminal fermentation and on concentrations of plasma hormone and metabolites in animals fed TMR demonstrate that infrequent sampling can result in misleading results and, thus, invalid interpretation of the influence of dietary fat on these parameters.

Ammonia↗
PubMed1992

Influence of rumen fermentable neutral detergent fiber levels on feed intake and milk production of dairy cows.

Sixteen dairy cows in midlactation were fed four isonitrogenous (mean 2.46% N) mixed rations containing 46.4% DM and 40.7% NDF in a 16-wk Latin square design experiment. Diets were 42% barley-based concentrate, on a DM basis; forage was provided by combinations of two timothy silages of either slow (poor timothy) or rapid (good timothy) rumen fermentability and an alfalfa silage. Differences between the timothy forages caused the 24-h in sacco mixed diet NDF fermentability, determined in dry cows fed hay, to be 53.8, 56.0, 60.2, and 62.1% in the four diets formulated to rise from 0% [as a percentage of total timothy DM] to 33, 66, and 100% good timothy. Intake of DM and NDF were not influenced by forage source. Rumen pool sizes of OM and NDF were similarly unaffected by treatment. Milk production increased linearly as the proportion of rapidly fermentable NDF in the diet increased, although the increases were small and not statistically significant, whereas BW gain declined (nonsignificantly). As a result, total net energy output was not influenced by diet. Although cows appeared able to extract more energy than expected from the slower fermenting forage, increasing levels in the diet resulted in a shift in energy output from milk products to BW gain, supported by a shift in rumen fermentation end products from propionic to acetic acid. Results do not appear to support the concept that NDF quality influences and can be used to predict voluntary feed intake. There is no indication that cows responded to more rapidly fermentable dietary NDF by increasing feed intake or extent of NDF fermentation in the rumen.

Ammonia↗
PubMed1991

Experimental microvenous reconstructions with Gore-Tex polytetrafluoroethylene prosthesis implanted by means of the sleeve anastomotic technique.

Polytetrafluoroethylene (PTFE) prostheses (Gore-Tex; ID, 1 mm; length, 5-7 mm; wall thickness, 0.2 mm; fibril length, 30 microns, n = 28) were implanted into the rat femoral vein by means of the sleeve anastomotic technique to enhance the patency rate. In the control group, PTFE prostheses (n = 8) were implanted by means of the end-to-end technique. In the experimental group patency and healing of the PTFE prostheses were evaluated at 1 day (n = 4), 1 week (n = 6), 3 weeks (n = 6), 6 weeks (n = 6), and 12 weeks (n = 6) after implantation by means of macroscopic inspection and routine light and scanning electron microscopy. All prostheses, except one at 1 week after implantation, were patent at the time of removal. All of the microvenous prostheses were completely covered by an endothelial layer at 3, 6, and 12 weeks after implantation. Occasionally some smooth muscle-like cells could be found underneath this endothelial layer, but stenosis was never observed at the anastomotic sites. Only scarce tissue ingrowth was observed in the wall of the PTFE prostheses. In the control group, all prostheses, except one prosthesis after 3 weeks, were found to be occluded. An occlusive mural thrombus was found firmly attached at the anastomoses at 1 day, and an organized thrombus at 3 weeks after implantation. The patent prosthesis demonstrated complete endothelial healing. These results demonstrate the importance of the sleeve anastomotic technique and the potential of PTFE prostheses as a microvenous conduit when implanted by means of the sleeve anastomotic technique in experimental reconstructive microvascular procedures.

Anastomosis, Surgical↗
PubMed1991

Nerve regeneration through a two-ply biodegradable nerve guide in the rat and the influence of ACTH4-9 nerve growth factor.

Biodegradable polyurethane-based (PU) nerve guides, instilled with or without ACTH4-9 analog (a melanocortin) were used for bridging an 8 mm gap in the rat sciatic nerve and were evaluated for function and histological appearance after 16 weeks of implantation. Autologous nerve grafts functioned as controls. The guides successfully enabled the sciatic nerve to regenerate across the 8 mm gap, thus effectively reestablishing the contact between the proximal and distal nerve ends. The mean conduction velocity, motor latency, and muscle action potentials of all the nerve guides did not differ significantly from the autografts. The histological quality of the regeneration in the nerve guides was significantly better than in the autografts; in the nerve guides, a well-defined nerve cable of normal architecture had regenerated without extensive endoneural scarring as seen in the autografts. ACTH4-9 instilled in the nerve guides showed a slight, but significant, increase in the number of myelinated axons. It is concluded that biodegradable PU nerve guides result in similar functional recovery when compared with autografts, but their histological quality is significantly better. ACTH4-9 showed only slight, but significant, improved nerve growth promoting activity. Therefore biodegradable PU nerve guides with ACTH4-9 would appear to be promising alternatives to autografts for bridging nerve defects.

Adrenocorticotropic Hormone↗
PubMed1991

Evaluation of results of temporal bone resection.

The results of 16 cases of temporal bone resection were evaluated. The resections, 12 of which were total and 4 partial, had mostly been performed for squamous cell carcinoma invading the temporal bone. Five patients in whom the intervention was considered radical and not followed by irradiation, were alive and well 9 years or more later. The significance of postoperative radiotherapy was demonstrated in 3 patients who were alive and in good health 9 years or more later, although histological examination of resection margins showed residual tumour. Eight patients died 10 months to 5 1/3 years after operation, 6 of whom from recurrence, one from radiation necrosis of the temporal lobe of the brain, and one from cerebrovascular occlusion. Histologically, squamous cell carcinoma was found significantly more among the patients who died from recurrence than among those still living.

Adult↗
PubMed1991

Influence of rumen undegradable protein levels on feed intake and milk production of dairy cows.

Twenty-seven dairy cows in midlactation were utilized in two experiments using 15 and 12 cows to determine effects of varying the delivery of ruminally undegraded protein on feed intake, milk production, and some rumen and plasma characteristics. In Experiment 1, cows consumed alfalfa silage ad libitum and one of three barley-based concentrates with either soybean meal (a rapidly rumen degraded protein source), corn gluten meal (a slowly degraded protein source), or an equal mixture of the two, fed at the rate of .36 kg/kg of milk produced. In Experiment 2, cows were fed total mixed diets based upon alfalfa silage, barley, and either soybean meal, corn gluten meal, or a mixture of soybean meal and whey powder (a protein source very rapidly degraded in the rumen). In sacco incubation procedures were used to estimate degradability of protein in all diets. All diets exceeded Agricultural Research Council recommendations for rumen degraded and undegraded protein as well as NRC recommendations for degraded protein. However, one to three of the six total diets, depending upon assumed ruminal turnover rates, did not meet NRC recommendations for undegraded protein. Production parameters, include DMI as well as milk yield and composition, were not influenced by diet in either experiment. Results do not support NRC recommendations for ruminally undegraded protein for midlactation dairy cows producing about 30 kg/d of milk and broadly support the lower recommendations of the Agricultural Research Council. Results also appear to question use of dietary energy intake to predict net rumen microbial protein yield.

Animal Feed↗
PubMed1991

Influence of canola fat on yield, fat percentage, fatty acid profile, and nitrogen fractions in Holstein milk.

Effects of canola fat on feed intake, yield, and composition of milk of early lactation dairy cows were investigated. Concentrate mixtures containing 0, 2.5, 5.0, 7.3, and 9.6% added fat as Jet-Sploded whole canola seed (0, 4.5, 9.0, 13.2, and 17.4% of DM, respectively) were fed to 15 cows in diets containing 60% concentrate and 40% forage (DM basis). Diets contained 16.5% CP, 30% alfalfa silage, and 10% whole crop oat silage (DM basis). There was a trend for a cubic effect on DMI, a quadratic effect on milk yield, and a small, but significant, linear decrease in milk protein percentage with increasing level of canola seed; the decrease was primarily in the casein fraction. Although milk fat percentage was not altered, addition of Jet-Sploded canola seed caused a substantial reduction in some short- and medium-chain fatty acids and a concomitant increase of as much as 65% in the concentration of C18:1. Results suggest that canola fat from Jet-Sploded whole canola seed can be included up to 5% of dietary DM without negative effects on DMI and with a net positive effect on milk yield.

Animals↗
PubMed1991

Hormonal responses to bovine somatotropin and dietary protein in early lactation dairy cows.

The effects of bST injection and dietary protein level on blood hormone and metabolite concentrations were examined in four mature Holstein cows in a double crossover design. Cows were assigned at d 5 to 9 postpartum to receive daily injections of either a control (saline) solution or 20.6 mg of bST. Four 3-wk periods were used during which one cow from each group was fed a medium protein diet (17.1% CP), and the other received a high protein diet (23.6% CP). Injections of bST or control solutions began on d 0 of the second period. Intakes of DM were not influenced by dietary protein or bST injection. Milk yield tended to increase with increased CP level but was not affected by bST injection. Based on the rate and extent of decline in milk production after cessation of bST injection, the cows assigned to bST had lower milk production potential than control cows. Thus, the effect of bST injection apparently was to enhance milk yield to levels similar to those of controls. There were no significant CP level or bST injection effects on glucose, FFA, somatostatin, or somatotropin concentrations. Glucagon concentrations were higher in bST-treated cows. Concentrations of insulin-like growth factor-I were increased with increased CP level and also with bST injection. Significant effects of days on bST were observed for insulin, insulin-like growth factor-I, glucose, and FFA. Cows given bST injections and producing equal amounts of milk as control cows did not show major physiological differences in hormones and metabolites with the exception of insulin-like growth factor-I.

Animals↗
PubMed1991

Effect of bovine somatotropin and protein on rumen fermentation and forestomach and whole tract digestion in dairy cows.

Four lactating Holstein cows with permanent ruminal and duodenal cannulas were allocated to one of two TMR with either 17.1 or 23.6% CP at 5 to 9 d postpartum. Cows also were assigned to either bST (20.6 mg/d) or excipient (control) treatment at that time for the 84-d experiment but were switched to different protein levels every 21 d in four periods. Intake of DM and forestomach and whole tract digestion of DM were unaffected by treatments. Forestomach and whole tract apparent digestion of N was higher for cows fed the high protein diet. Forestomach NDF and ADF digestion was higher for cows fed the high protein diet but was significant for control cows only. Rumen pH, ammonia N, and isovalerate were higher for cows fed the high protein diet. Rumen ammonia N and acetate were lower for bST-treated cows. Rumen pool sizes of total ingesta, DM, NDF, and bacterial OM were not affected by either treatment. However, the total pool size of rumen NAN and nonbacterial NAN was larger for cows fed the high protein diet. Duodenal flow of AA was higher for cows fed the high protein diet. However, duodenal protein AA profiles were similar among treatments except for lysine, which was higher, and methionine and alanine, which tended to be lower, for cows fed the high protein diet. There were few bST x protein or bST x duration of treatment interactions. Results support the concept that bST-treated cows have digestive metabolism similar to untreated cows of similar actual production.

Animal Feed↗
PubMed1990

Two-ply biodegradable nerve guide: basic aspects of design, construction and biological performance.

A synthetic biodegradable nerve guide was constructed of two polymeric layers: an inner microporous layer prepared from a copolymer of L-lactide and epsilon-caprolactone (pore size range 0.5-1 micron) and an outer microporous layer prepared from a polyurethane/poly(L-lactide) mixture (pore size range 30-70 microns). This nerve guide was used to bridge a 7 mm gap in the right sciatic nerve of rats. It enabled the sciatic nerve to regenerate across the gap, forming a new, well-defined nerve that effectively re-established the contact between the proximial and distal nerve end, as effective as an autograft.

Adrenocorticotropic Hormone↗
PubMed1979

Pericarditis.

Explore the source record for details and available documents.

Acute Disease↗
PubMed1978

Value of coronary bypass surgery. Controversies in cardiology: Part I.

The value of coronary bypass surgery has been studied carefully during the last decade. Four methods, none perfect, have been used to compare the results of such surgery with the results of medical therapy. New data are likely to be merely supportive rather than the outcome of a definitive study with a new and a acceptable experimental design. It is therefore time to analyze the available data in light of the treacherousness of the disease and to determine if a clear trend is evident. There appears to be sufficient evidence to state that properly performed coronary bypass surgery will increase coronary blood flow and relieve angina pectoris in 90 percent of patients; total relief of angina can be expected in 60 percent and partial relief in 30 percent. Compared with modern medical therapy, properly performed coronary bypass surgery appears to prolong the life of patients who have obstruction of the left main coronary artery or triple or double vessel disease. There is not adequate evidence to state that the procedure will prolong the life of patients with single vessel obstruction. However, patients with single vessel obstruction and unacceptable angina pectoris should be considered for bypass surgery (especially patients with obstruction of the left anterior descending coronary artery). In practice, at Emory University Hospital, Atlanta, bypass surgery is recommended for young people with few symptoms if compelling obstructing lesions are present and in older patients only if their symptoms require it. Medical therapy is given before and after bypass surgery. When bypass surgery is performed in an excellent fashion (operative risk 1 percent) a great deal of "controversy" about this problem vanishes.

Angina Pectoris↗
PubMedDate not supplied

Reduced thrombogenicity of vascular prostheses by coating with ADP-ase.

In this pilot study ADP-ase coated polyurethane (PU) vascular prostheses and noncoated (control) PU vascular prostheses (all vascular prostheses: ID 1.5 mm, length 1.5 cm) were implanted into the carotid artery of the rabbit to test whether ADP-ase might function as an adequate anti-thrombogenic coating. The prostheses were evaluated after 1 hour (n = 4) and 3 weeks (n = 8). After 1 hour, there was extensive accumulation of thrombus on the inner surface of the control PU vascular prostheses, in contrast to the ADP-ase coated prostheses. At 3 weeks, all control PU vascular prostheses (n = 8) were occluded, whereas only 1 of the 8 ADP-ase coated PU vascular prostheses. The patient ADP-ase coated PU prostheses showed already extensive endothelial healing. These results indicate the potential of ADP-ase to function as an effective antithrombogenic coating of small-caliber and microvascular PU prostheses.

Animals↗